I have two points I want to clarify. First, it must be understood that a firearm is the ideal instrument with which to commit suicide or homicide, because it gives the attacker an incredible advantage over his victim. It enables him to kill the person more quickly and impersonally. A lot of people wouldn't commit a homicide or commit suicide with a knife if they didn't have a firearm within reach because they would be unable to do so. Consider the example of a 100-pound woman who attacks a 200-pound man; the firearm gives her an incredible power over her victim. The difference in strength between the individuals involved is no longer so important when a firearm is involved, but it remains if a knife is used.
The second thing you have to know is that, while knives are used as much in homicides, while they are used in the same proportion, that is particularly as a result of effective firearms control. The percentage of homicides committed by knife may increase at the same time as the homicide rate in general declines. It's because the rate of homicide by firearms is falling that the rate of homicide by knife is increasing. However, that doesn't mean that knives are more dangerous.
That's why these statistics must be compared with the trend in rates of homicide by firearms or by other methods.